Calm Weekend, Early Week Rain

FastCast--Sunday, Dec. 17 to Wednesday, Dec. 20:

After a calm and relatively uneventful week, similar conditions are expected this weekend. On Sunday morning, expect lows reaching the low to mid 30s across the lowlands, with partly sunny conditions and highs in the mid to upper 40s. Monday will be cloudy with evening showers. That rain will continue into Tuesday, tapering off by afternoon. The lowlands will receive 0.4-0.6" of rain, with isolated higher amounts. On Monday, expect highs in the mid 40s, increasing to the low 50s by Tuesday and Wednesday. Expect Wednesday to be partly cloudy, with highs in the low 50s. Lows through midweek will reach the upper 30s to low 40s. 

Air quality will be stagnant at times over the next few days. Check air quality below:

Washington State Air Quality Map (PurpleAir)

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Continue reading the full blog below!

Calm weather will continue for the next few days across Washington, with a weak system bringing a round of rain from Monday to Tuesday. Let's take a look at the forecast!

On Sunday morning, lows across the state will be on the chilly side. Below is the European model forecast.

In the lowlands, expect lows in the low 30s, with some areas staying in the mid 30s. The coast will only drop to the upper 30s to low 40s, with the Willamette Valley dropping to the low to mid 30s. Eastern Washington will be much colder, dropping to the low 20s near Spokane and the mid to upper 20s elsewhere.

Now, let's take a look at the upcoming system. Below is the European model forecast for rain through early Wednesday.

This forecast shows the lowlands getting 0.5-0.7", with isolated areas getting up to 1". The coast and Willamette Valley will get 0.4-0.9", and Eastern Washington will get 0.1-0.3". 

Let's compare this to the GFS forecast, seen below.

This forecast shows 0.4-0.5" for the lowlands, with the coast getting 0.5-0.7", and Eastern Washington getting 0-0.2". 

Now, let's take a look at the snow forecast from the European model, through early Wednesday.

Snow won't be too impressive, with 0.5-2" at the passes (most at Stevens Pass). Most snow (4-6") will fall in the North Cascades backcountry. 

Now, let's take a look at the extended forecasts from the NWS Climate Prediction Center (CPC) for December 24-30. 

Below is the temperature outlook.

This is a classic El Niño pattern for winter, showing significantly above average temperatures for the entirety of the Lower 48, especially in the High Plains and Upper Midwest. The Northwest will have a 50-60% probability of above average temperatures through Christmas and New Year's.

Let's round out the blog by looking at the precipitation outlook, seen below.

Again, in a classic El Niño pattern, the northern tier of the US (with the exception of Washington) will likely have below average precipitation, with California and the southern tier of the country getting above average precipitation. In Western Washington, there is a 40-50% probability of above average precipitation, with a 30-40% probability of above average precipitation for Eastern Washington.

Enjoy the calm and non-impactful weather as holiday travel ramps up!